Neuroscientists at Princeton created a new way to study the neurons of the classic mouse-in-a-maze: Strap it to a suspended ball and have it run through a virtual maze. That first virtual maze? Derived from a Quake 2 level.

Apparently it's difficult to control and study the neurons of a mouse when it's physically moving, and this method makes that easier. The ball is suspended on a jet of air, and the mouse is strapped in place with a collar on top of it (like a giant trackball, sort of). Given that I don't understand psychology at all, or even totally know what a neuron is, I'm going to go ahead and assume this is an elaborate ruse to get a mouse to play Quake 2. Well played, scientists. [Pop Sci]